When was the last time you saw a tube tester at a drug store? I used to hunt in a remote [roadless] area in Alaska that was a former DEW site in the 50's. Most of the structures were long gone, but when they demolished them apparently they hauled all the electronics to a big dump. There were huge rack's of electronics laying around, all filled with hundred's of vacuum tubes. Remember this was military, so it was state of the art.
I suppose the same function could be accomplished today with something you could put in your shirt pocket.